Method, system, and computer program for controlling a hydraulic press

Abstract

A method, control system, computer program, and article of manufacture for controlling hydraulic press systems, and a new press system that utilizes a number of improvements over the assignee's original system. The control system is designed to control a hydraulic press having a die, at least two separate sets of workpiece forming punches, and at least two hydraulic pistons, each operatively associated with one set of workpiece-forming punches. The control system includes a means for controlling a magnitude of a pressing force applied by each set of workpiece-forming punches, and a means for controlling a position of each set of workpiece-forming punches relative to the die.

1. A method for controlling a powder press, the method comprising the steps of:
 introducing a powder material into a die; 
 creating a substantially uniform distribution of powder material in the die by fluidization of the powder as the powder enters the die; 
 pressing of the powder material in the die by controlling a pressure of a fluid provided to each of at least one piston that is operatively associated with each set of workpiece-forming punches therein controlling a magnitude of a pressing force applied by each set of workpiece-forming punches including the steps of:
 determining a pressure of a fluid provided to each of at least one piston that is operatively associated with each set of workpiece-forming punches, comparing using at least one pressure sensor and a processor the pressure of the fluid provided to each piston to a pressure corresponding to a desired pressing force, and 
 adjusting the pressure of the fluid provided to each piston based upon a result of the comparing step; and 
 
 controlling a position of each set of workpiece-forming punches relative to the die using a position sensor and the processor. 
 
     
     
       2. A method as claimed in  claim 1  wherein the step of introducing the powder material comprises the step of controlling a weight of the powder material introduced into the die. 
     
     
       3. The method as claimed in  claim 2  wherein the step of controlling the weight of the powder material introduced into the die comprises the steps of controlling a weight of a first powder material to be introduced into the die and controlling a weight of a second powder material to be introduced into the die. 
     
     
       4. A method as claimed in  claim 1  wherein the step of introducing the powder material comprises the step of controlling a temperature of the powder material to be introduced into the die. 
     
     
       5. The method as claimed in  claim 1  further comprising the step of heating a pressurized gas used to fluidize the powder material within the die. 
     
     
       6. The method as claimed in  claim 1  wherein the step of adjusting the pressure of the fluid provided to each piston comprises adjusting the pressure of the fluid provided to each piston such that the workpiece-forming punches form a workpiece having a substantially uniform density. 
     
     
       7. A method as claimed in  claim 1  wherein the step of controlling the pressing of the powder material in the die further comprises controlling positioning a first set of workpiece-forming punches relative to the die by controlling the position using a position sensor and the processor, and positioning a second set of workpiece forming punches relative to the die by controlling the position using a position sensor and the processor. 
     
     
       8. A method as claimed in  claim 1  wherein said step of controlling the pressing of the powder material in the die comprises controlling the pressing of the powder material such that a finished part does not crack upon ejection, said controlling comprising the steps of:
 pressing the powder material to a desired position; and 
 gradually reducing the pressing force applied by each of at least one set of workpiece-forming punches while maintaining the workpiece forming punches in a substantially fixed position such that the finished part is fully supported at all times prior to ejection; and 
 ejecting the finished part. 
 
     
     
       9. A method for controlling a powder press, the method comprising the steps of:
 introducing a powder material into a die by measuring the feed of powder material onto a scale controlled by a controller for introduction into the die; 
 creating a substantially uniform distribution of powder material in the die by fluidization of the powder as the powder enters the die; 
 pressing of the powder material in the die by controlling a pressure of a fluid provided to each of at least one piston that is operatively associated with each set of workpiece-forming punches therein controlling a magnitude of a pressing force applied by each of at least one set of workpiece-forming punches; and 
 by controlling a position of each set of workpiece-forming punches relative to the die including the steps of:
 determining a position of each set of workpiece-forming punches, comparing using a position sensor and the controller the position of each set of workpiece-forming punches to a desired position, and 
 adjusting a rate of travel of each set of workpiece-forming punches based upon a result of the comparing step. 
 
 
     
     
       10. A method for controlling a powder press, said method comprising the steps of:
 lubricating the die cavity; 
 introducing a powder material into a die; 
 creating a substantially uniform distribution of powder material in the die by fluidization of the powder as the powder enters the die; and 
 pressing of the powder material in the die by controlling a magnitude of a pressing force applied by each of at least one set of workpiece-forming punches by 
 determining a pressure of a fluid provided to each of at least one piston that is operatively associated with each set of workpiece-forming punches, 
 comparing using at least one pressure sensor and a processor the pressure of the fluid provided to each piston to a pressure corresponding to a desired pressing force, and 
 adjusting the pressure of the fluid provided to each piston based upon a result of the comparing step and by controlling a position of each set of workpiece-forming punches relative to the die using at least one position sensor and the processor. 
 
     
     
       11. The method as claimed in  claim 10  wherein the step of adjusting the pressure of the fluid provided to each piston comprises adjusting the pressure of the fluid provided to each piston such that the workpiece-forming punches form a workpiece having a substantially uniform density. 
     
     
       12. The method as claimed in  claim 10  wherein said step of lubricating of the die cavity comprises the steps of:
 creating an enclosed die cavity; 
 introducing a lubricant into the die cavity; and 
 draining the lubricant from the die cavity.